by Brigit » Wed Feb 26, 2020 9:03 pm
VAN DER WAALS, JOHANNES DIDERIK (1837-1923), Dutch physicist, was born at Leiden, Nov. 23, 1837. At Leiden University he attracted scientific interest in 1873 by his thesis on the continuity of the liquid and gaseous conditions. He became professor of physics at the University of Amsterdam in 1877. He became known for his new derivation of an equation of state for gases, which went far beyond the laws of Robert Boyle and Joseph Gay-Lussac; his work in the kinetic theory of gases, and its application to fluids, and the extension of this, by means of "critical" values, to the "law of corresponding states." He retired from the University in 1907, was awarded the Nobel Prize in physics in 1910, and died at Amsterdam, on Mar. 9, 1923.
VAN DER WAALS' EQUATION, a relation between pressure, volume and temperature for pure gases and liquids formulated as follows:
(p + a/V^2) (V - b) = RT
Here p is the pressure; V is the volume occupied by one gram-molecular weight of the gas; T is the absolute temperature; and R is the gas constant, the same for all gases. The constnts a and b, the so-called van der Waals' constants, are characteristic of the gas in question.
The term (a/V^2) represents a pressure effect due to the attractions between the molecules which assist the externally applied pressure in compressing the gas;
b represents the small volume occupied by the molecules themselves which sets a limit to the compression experienced by the gas under very high pressures, since the free space subject to change is then only (V - b). At high tempreatures and low pressures, the equation reduces to the ideal gas law pV = RT. See Boyle's Law. L.O.C (National Encyclopedia 1944)
[b]VAN DER WAALS, JOHANNES DIDERIK[/b] (1837-1923), Dutch physicist, was born at Leiden, Nov. 23, 1837. At Leiden University he attracted scientific interest in 1873 by his thesis on the continuity of the liquid and gaseous conditions. He became professor of physics at the University of Amsterdam in 1877. He became known for his new derivation of an equation of state for gases, which went far beyond the laws of Robert Boyle and Joseph Gay-Lussac; his work in the kinetic theory of gases, and its application to fluids, and the extension of this, by means of "critical" values, to the "law of corresponding states." He retired from the University in 1907, was awarded the Nobel Prize in physics in 1910, and died at Amsterdam, on Mar. 9, 1923.
[b]VAN DER WAALS' EQUATION[/b], a relation between pressure, volume and temperature for pure gases and liquids formulated as follows:
[i](p + a/V^2) (V - b) = RT[/i]
Here [i]p[/i] is the pressure; [i]V[/i] is the volume occupied by one gram-molecular weight of the gas; [i]T[/i] is the absolute temperature; and[i] R [/i]is the gas constant, the same for all gases. The constnts [i]a[/i] and [i]b[/i], the so-called van der Waals' constants, are characteristic of the gas in question.
The term [i](a/V^2)[/i] represents a pressure effect due to the attractions between the molecules which assist the externally applied pressure in compressing the gas;
[i]b[/i] represents the small volume occupied by the molecules themselves which sets a limit to the compression experienced by the gas under very high pressures, since the free space subject to change is then only[i] (V - b)[/i]. At high tempreatures and low pressures, the equation reduces to the ideal gas law[i] pV = RT. [/i]See Boyle's Law. L.O.C (National Encyclopedia 1944)